.navbar {
  position: fixed;
  top: 60px;
  left: 7px;
  padding: 8px;
  border-radius: 50px;
  background-color: cadetblue;
  margin: 10px auto;
  width: 30px;
  height: 30px;
  transition: all 0.4s;
}
.navbar input {
  width: 30px;
  height: 30px;
  opacity: 0;
  cursor: pointer;
}
.navbar .navBtn {
  position: absolute;
  top: 22px;
  left: 11px;
  width: 25px;
  height: 4px;
  border-radius: 15px;
  background: wheat;
  /* 元素永远不会成为鼠标事件的target，也就是无法点击*/
  pointer-events: none;
  transition: transform 0.3s ease-in-out, top 0.3s ease-in-out 0.3s;
}
.navbar .content {
  width: 0;
  transition: all 0.5s;
}
.navbar .content img {
  margin: 10px 0;
  width: 30px;
  height: 30px;
}
.navbar input:checked ~ span:nth-child(2) {
  transform: rotate(-45deg);
  transition: all 0.3s;
}
.navbar input:checked ~ span:nth-child(3) {
  transform: rotate(45deg);
  transition: all 0.3s;
}
.navbar input:hover ~ span:nth-child(2) {
  transform: rotate(90deg);
  transition: all 0.5s;
}
.navbar input:hover ~ span:nth-child(3) {
  transform: rotate(-180deg);
  transition: all 0.5s;
}

.colorPicture:hover,
.sizePicture:hover,
.eraserPicture:hover,
.blurPicture:hover,
.deepPicture:hover,
.undoPicture:hover,
.oldPicture:hover,
.redoPicture:hover,
.formPicture:hover {
  cursor: pointer;
  transform: scale(1.2);
  transform: rotate(90deg);
  transition: all 0.5s;
}
.sizePicture,
.colorPicture,
.eraserPicture,
.blurPicture,
.deepPicture,
.oldPicture,
.undoPicture,
.redoPicture,
.formPicture {
  display: none;
  font-size: 30px;
  transition: all 0.5s;
}
